Zhang Zhenzhen, Guo Cheng, Cui Liang, Mo Qi, Zhao Ningbo, Du Cheng, Li Xiaoying, Li Guifang
Opt Lett. 2018 Apr 1;43(7):1550-1553. doi: 10.1364/OL.43.001550.
We experimentally demonstrate a 12-mode group (21 spatial mode) cladding-pumped few-mode erbium-doped fiber amplifier. The differential modal gain (DMG) is dramatically reduced by using the double cladding erbium-doped fiber (DC-EDF) with a refractive index trench structure, which helps to tightly confine all 21 spatial modes in the core and to mitigate the bending loss. Our experimental results show that the DMG gain is about 3 dB when the average signal modal gain for all 12 mode groups is up to 15 dB across the C-band. Our method of using a DC-EDF with a properly designed trench structure can be used to develop gain equalized few-mode amplifiers supporting more spatial modes.
我们通过实验演示了一种12模组（21个空间模式）包层泵浦少模掺铒光纤放大器。通过使用具有折射率沟槽结构的双包层掺铒光纤（DC-EDF），差分模式增益（DMG）显著降低，这有助于将所有21个空间模式紧密限制在纤芯中，并减轻弯曲损耗。我们的实验结果表明，当所有12个模组的平均信号模式增益在整个C波段达到15 dB时，DMG增益约为3 dB。我们使用具有适当设计沟槽结构的DC-EDF的方法可用于开发支持更多空间模式的增益均衡少模放大器。
